JPH09281555A - Pentagonal mirror supporting structure for single-lens reflex camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate need for leaving a pentagonal mirror as it is for a long time until adhesive agent for fixing it is hardened and to prevent the positional deviation of the pentagonal mirror caused by the contraction,of the adhesive agent from occurring by interposing an elastic material between a protection cover fixed to a mirror box block and set for covering a roof reflector by leaving a fixed interval and the roof reflector. SOLUTION: The pentagonal mirror 20 is provided with the roof reflector 23 consisting of a pair of mutually orthogonally crossed plate parts 21 and 22 and constituted so that reflecting surfaces 21a and 22a are formed on the inside surface of the respective plates part 21 and 22 by the evaporation of aluminum or the like. Besides, the mirror 20 is provided with a reflector 25 having a reflecting surface reflecting light reflected on the reflection surfaces 21a and 22a toward an eyepiece side and constituted so that a foamed uretane piece(elastic material) 40 is stuck to a ridge part 24. Then, the mirror 20 is made to adhere to the left and the right side walls 15 and 16 of the mirror box block 10 by silicone bond B. Besides, the protection cover 50 covering the reflector 23 by leaving the fixed interval is fixed to the block 10 and the piece 40 is interposed between the cover 50 and the reflector 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera using a pentamirror, and more particularly to a support structure for the pentamirror.

[0002]

2. Description of the Related Art Pentagonal roof prisms (commonly called "penta prisms") are widely used in single-lens reflex cameras to obtain an erect observation image. The pentaprism made of solid glass has excellent optical characteristics, but is heavy, and is a component that prevents the weight reduction of the camera.

Recently, in order to reduce the weight of a single-lens reflex camera, instead of a heavy pentaprism, a pentamirror having a hollow interior in which a roof reflecting surface and a third reflecting surface are formed of reflecting plates (mirrors) is used. The existing single-lens reflex camera has been commercialized. The pentamirror is made of synthetic resin, and aluminum or silver is deposited on the inner surface of the frame to form a roof reflection surface and a third reflection surface.

When a pentaprism is fixed on a mirror box block (mirror box) that supports a quick return mirror or the like, it is usually pressed against the mirror box block using a spring, a holding plate or the like. When fixing the pentamirror on the mirror box block, if it is fixed in the same fixing direction as the pentaprism, it will be deformed due to low strength, so it is usually bonded to the mirror box block using an adhesive such as silicon bond. The way to do is taken.

However, conventionally, there have been the following problems in fixing the pentamirror to the mirror box block using an adhesive. In other words, it is necessary to leave it for a long time without giving vibration or the like until the adhesive is hardened, so that the production efficiency is poor, and because the pentamirror made of synthetic resin is lightweight, the pentamirror may shrink due to the contraction of the adhesive. There was a case that it floated up from the mirror box block and shifted from the regular position. When this displacement occurs, it is naturally impossible to obtain a normal viewfinder field.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and in an SLR camera having a structure in which a pentamirror is fixed to a mirror box block via an adhesive, It is an object of the present invention to provide a pentamirror support structure that does not need to be left for a long time until the agent is completely cured, and that can reliably prevent displacement of the pentamirror due to contraction of the adhesive.

[0007]

SUMMARY OF THE INVENTION A pentamirror support structure for a single-lens reflex camera of the present invention comprises a roof reflector having a pair of reflecting surfaces orthogonal to each other, and third reflection for reflecting the light reflected by the pair of reflecting surfaces to the eyepiece side. A penta mirror provided with a third reflector having a surface; a mirror box block to which the penta mirror is bonded; a roof mirror block fixed to the mirror box block with a certain distance from the roof reflector plate With protective cover;
An elastic material sandwiched between the protective cover and the roof reflector is provided.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. FIG. 1 shows a main part of an embodiment of a single-lens reflex camera to which the present invention is applied. 2 is an exploded perspective view of the main part, and FIG. 3 is a vertical cross-sectional view of the main part shown in FIG.

The mirror box block 10 is fixed in a camera body (not shown) of a single-lens reflex camera, and a quick return mirror 12 (see FIG. 3) is attached to a shaft 11 (see FIG. 3) extending in the left-right direction of the camera. (Indicated by the one-dot chain line in FIG. 3). The mirror box block 10 has a focusing plate 13 (shown by a chain double-dashed line in FIG. 3) above the quick return mirror 12. The subject light that has passed through a photographing lens (not shown) mounted in front of the mirror box block 10 (on the left in FIG. 3) is reflected upward by the quick mirror 12 and is optically reflected by the film surface (not shown). An image is formed on the focusing plate 13 arranged at a position equivalent to. The focusing plate 13 is fixed to the lower portion of the prism sheet portion 14 on which the pentamirror 20 is placed.

The pentamirror 20 has a roof reflection plate 23 composed of a pair of plate portions 21 and 22 which are orthogonal to each other. Reflective surfaces 21a and 22a are formed on the inner surfaces of the plate portions 21 and 22 by vapor deposition of aluminum, silver, or the like.
The pair of reflecting surfaces 21a and 22a constitutes a roof reflecting surface.

The pentamirror 20 has a reflecting surface 21a,
A third reflecting plate 25 forming an angle of 45 ° with a ridgeline 23a formed by 22a.
have. A third reflection surface 25a is formed on the inner surface of the third reflection plate 25 by vapor deposition of aluminum, silver, or the like, like the reflection surfaces 21a and 22a. The ridge line 23a
On the ridge 24 of the pentamirror 20 along the ridge 2
4, a urethane foam piece 40 having a predetermined thickness is attached. This urethane foam piece 40, as shown in FIG.
It is provided closer to the eyepiece lens 26 than the vertical line L drawn from the front end of the lower end (that is, the lower end 25b of the third reflection plate 25) to the ridge line 23a.

Further, the pentamirror 20 has a triangular connection light-shielding plate 30 for connecting the roof reflector 23 and the third reflector 25 on the front surface of the upper part thereof. The inner surface of the connection light-shielding plate 30 is a rough surface to prevent reflection of light incident on the inner surface.

The bottom edge 31 of the pentamirror 20 is placed on the prism sheet portion 14 formed on the mirror box block 10. A pair of positioning protrusions 32 extending downward is provided on one side of the bottom edge 31 of the pentamirror 20. The pair of positioning protrusions 32 are respectively fitted into a pair of positioning holes (not shown) formed at corresponding portions of the prism sheet portion 14, and thereby the pentamirror 20 is positioned with respect to the prism sheet portion 14. . The penta mirror 20 is positioned by the pair of positioning protrusions 32 and the pair of positioning holes, and then the silicon bond B is injected between the upper ends of the left and right side walls 15 and 16 of the mirror box block 10 and the penta mirror 20. Then, the pentamirror 20 is bonded to the mirror box block 10.

Immediately after this bonding work, the protective cover 50 is fixed to the upper part of the pentamirror 20. This protective cover 50
Is made of a metal material such as stainless steel or aluminum and has a bilaterally symmetrical shape. The protective cover 50 includes a pair of protective plates 51 and 52 along the pair of plate portions 21 and 22 of the pentamirror 20, fixed leg plates 53 and 54 integrally formed at the lower rear ends of the protective plates 51 and 52, Each protection plate 5
Positioning protrusions 55 and 56 are integrally formed at the lower ends of the front portions of the first and the second portions 52. The fixed leg plates 53 and 54 are located on the same plane, and the respective projecting portions 55 and 56 project downward.

In the protective cover 50 having the above structure, the protrusions 55 and 56 are provided on the left and right side walls 15 and 1 of the mirror box block 10.
Positioning recesses 15a and 16a formed at the upper end of each
In a state where the screw insertion holes 57 formed in the fixed leg plates 53 and 54 are aligned with the corresponding screw holes 15b and 16b formed in the upper ends of the left and right side walls 15 and 16, respectively. Pass the screw 58 through the screw insertion hole 57 and each screw hole 1
It is fixed to the mirror box block 10 by being screwed into 5b and 16b. In this fixed state, the pair of plate portions 21 and 22 of the pentamirror 20 and the pair of protection plates 51 and 52
A fixed gap S is formed between and, so that the protective cover 50 is not in contact with the pentamirror 20.

In the state where the protective cover 50 is fixed to the mirror box block 10, the urethane foam piece 40 attached on the ridge portion 24 of the pentamirror 20 is compressed in the gap S. That is, the urethane foam piece 40 is sandwiched between the ridge portion 24 of the pentamirror 20 and the ridge portion 59 of the protective cover 50 formed of the pair of protection plates 51 and 52. Therefore, the urethane foam piece 40 makes elastic contact with the ridge portion 24 of the pentamirror 20.
Is pressed toward the prism sheet portion 14.

As described above, the urethane foam piece 40 is provided on the ridge portion 24 closer to the eyepiece lens 26 than the vertical line L shown in FIG. This is the urethane foam piece 40 with a vertical line L
When it is provided in front of (the left side in FIG. 3), the pentamirror 20 tilts forward with the lower end portion 25b of the third reflection plate 25 as an axis by the elastic force (restoring elastic force) of the compressed urethane foam piece 40. This is because it will end up.

As described above, in the above-described embodiment of the single-lens reflex camera to which the present invention is applied, the protective cover 50 is fixed to the upper portion of the pentamirror 20 immediately after the pentamirror 20 is bonded to the mirror box block 10. By this fixing, the urethane foam piece 40 elastically contacts the ridge portion 24 of the pentamirror 20, and presses the pentamirror 20 against the prism sheet portion 14. Therefore, the pentamirror 20 is attached to the mirror box block 10
Even if the pentamirror 20 tries to float up from the mirror box block 10 due to the contraction of the silicon bond B after the bonding, the elastic force of the urethane foam piece 40 prevents the pentamirror 20 from rising. It should be noted that the urethane foam piece 40 is formed in the gap S so as to elastically contact the ridge portion 24 with a weak elastic force required to prevent the pentamirror 20 from rising from the mirror box block 10 due to the contraction of the silicon bond B. The dimensions such as the interval and the thickness of the urethane foam piece 40 are strictly set in advance.

When a urethane foam piece is provided between the pentamirror 20 and the protective cover 50, the pair of plate portions 2 in the gap S is formed.
It is conceivable that a urethane foam piece is provided between each of the protective plates 51 and 52 and the protective plates 51 and 52. In this configuration, when the elastic force of the urethane foam piece is particularly large, the plate portions 21 and 22 are bent by the elastic force, and as a result, the reflecting surfaces 21a,
22a may be distorted. In the present embodiment, since the urethane foam piece 40 is elastically contacted with the ridge portion 24 having relatively high strength, the reflecting surface 21 is elastically affected by the elastic force of the urethane foam piece.
There is no distortion of a and 22a.

In the above embodiment, the urethane foam piece 40 is used.
Is a ridge portion 2 on the eyepiece lens 26 side with respect to the vertical line L shown in FIG.
4, which is provided on a part of the upper side of the eyepiece 4,
The structure may be provided over the entire ridge portion 24 on the 6 side. Further, the urethane foam piece 40 may be provided over the entire ridge portion 24.

In the above embodiment, the urethane foam piece 40 is attached to the ridge portion 24, but instead of this arrangement, the urethane foam piece 40 may be attached to the inner surface of the ridge portion 59 of the protective cover 50.

In the above embodiment, the silicon bond B is used as the adhesive for bonding the pentamirror 20 to the mirror box block 10, but other adhesives may be used.

In the above embodiment, the urethane foam piece 40 is used as the elastic material sandwiched between the protective cover 50 and the roof reflection plate 23, but instead of the urethane foam piece 40, the elastic force is relatively weak. The elastic material may be provided.

As described above, in the above embodiment to which the present invention is applied, the lens box block of the pentamirror 20 due to the contraction of the silicon bond B by the elastic force of the urethane foam piece 40 without deforming the pentamirror 20. 10
Lifting from above is reliably prevented. Further, since the protective cover 50 is fixed to the upper part of the pentamirror 20 immediately after the pentamirror 20 is bonded to the mirror box block 10, it is necessary to leave the pentamirror 20 and the mirror box block 10 for a long time until the silicon bond B is completely cured. There is no. Therefore, production efficiency is increased.

[0025]

As described above, according to the pentamirror support structure of the single lens reflex camera of the present invention, since the elastic material is sandwiched between the protective cover and the roof reflector, the adhesive is completely cured. It is not necessary to leave it for a long time until it is removed, and it is possible to reliably prevent the pentamirror from being displaced from the regular position due to the contraction of the adhesive. Further, if the elastic material is provided along the ridgeline of the roof reflector, it is possible to reliably prevent the pentamirror from being distorted by the elastic force of the elastic material.

[Brief description of drawings]

FIG. 1 is a perspective external view showing a main part of an embodiment of a single-lens reflex camera to which the present invention has been applied.

FIG. 2 is an exploded perspective view of the main part shown in FIG.

FIG. 3 is a vertical sectional view of a main part shown in FIG.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1;

[Explanation of symbols]

 10 Mirror Box Block 20 Penta Mirror 21 22 Plate 23 Dach Reflector 21a 22a Reflective Surface (A Pair of Reflective Surfaces) 23 Dach Reflective Surface 23a Ridge 25 Third Reflector 25a Third Reflective Surface 26 Eyepiece 40 Foam Urethane Piece 50 Protection Cover L perpendicular

Claims (5)

[Claims] 1. A penta reflector comprising a roof reflector having a pair of reflecting surfaces orthogonal to each other, and a third reflector having a third reflecting surface for reflecting the light reflected by the pair of reflecting surfaces to the eyepiece side. A mirror; a mirror box block to which the pentamirror is bonded; a protective cover fixed to the mirror box block and covering the roof reflector plate at a constant interval from the roof reflector plate; A pentamirror support structure for a single-lens reflex camera, comprising: an elastic material sandwiched between the roof reflector and the roof reflector. 2. The pentamirror support structure for a single-lens reflex camera according to claim 1, wherein the elastic material is provided along a ridgeline of the roof reflector. 3. The single-lens reflex camera according to claim 2, wherein the elastic member is provided closer to the eyepiece lens than a vertical line drawn from the front end of the lower end of the pentamirror abutting the mirror box block to the ridgeline of the roof reflector. Penta mirror support structure. 4. The pentamirror support structure for a single-lens reflex camera according to claim 1, wherein the elastic material is previously attached to either the protective cover or the roof reflector. 5. The pentamirror support structure for a single-lens reflex camera according to claim 1, wherein the elastic material is urethane foam.